The invention relates to an apparatus for needling a non-woven material with a support receiving at least one needleboard, which support is drivable in a reciprocating fashion both in the needle-penetration direction as well as the direction of passage of the non-woven material and on which are coupled the connecting rods of two oppositely driven eccentric drives for the drive in the needle-penetration direction, and with a device for setting the movement component of the support in the direction of passage of the non-woven material.
In order to reduce the draft of a non-woven material drawn continuously by a needling apparatus on the one hand and to increase the advance of the non-woven material on the other hand it is known (DE 196 15 697 A1) to provide an additional eccentric drive for a needleboard movement in the direction of passage of the non-woven material in addition to the needleboard drive reciprocating in the needle-penetration direction, so that due to the movement component of the needles in the direction of passage of the non-woven material the tensile load of the nonwoven material as occurs during the needle penetration is reduced or the advance of the non-woven material is increased accordingly. In order to set the oscillating amplitude of the needleboard in the direction of passage of the non-woven material, it has already been proposed in this connection (EP 0 892 102 A2) to equip the additional needleboard drive with two parallel eccentric shafts whose connecting rods are mutually connected by a coupler linked to a support for the needleboard. By making a respective choice of the mutual angular position of the two eccentric shafts it is possible to set the needleboard advance in the direction of passage of the non-woven material. This simple possibility for adjustment is gained with the disadvantage that the support which is coupled with the connecting rods of the two eccentric drives for the needleboard drive in the needle-penetration direction performs a reciprocating swiveling movement which produces a respective swiveling movement of the needles in the non-woven material during the needle penetration.
The invention is thus based on the object of providing an apparatus for needling a non-woven material of the kind mentioned above in such a way that advantageous conditions are provided on the one hand for a construction of a needleboard drive of low complexity both in the needle-penetration direction as well as in the direction of passage of the non-woven material and on the other hand for a simple setting of the needleboard advance in the direction of passage of the non-woven material without having to swivel the needleboard.
This object is achieved by the invention in such a way that the connecting rods of the two oppositely driven eccentric drives extend in opposite directions with respect to the needle-penetration direction, that the additional eccentric drive revolves synchronously with one of the two other eccentric drives, that the connecting rod of the additional eccentric drive which is also coupled with the support forms a parallelogram of links for guiding the support with the connecting rod of the synchronously revolving eccentric drive, and that the oppositely drivable eccentric drives are provided with separate motors which are adjustable with respect to their mutual rotational angle position via a control device.
Since the connecting rods of the two oppositely drivable eccentric drives for the needleboard drive in the needle-penetration direction are not provided, as is otherwise usual, with a central position extending in the needle-penetration direction but extend inclined in opposite directions with respect to the needle-penetration direction, the support for the needleboard can be driven along an inherently closed trajectory by a phase shift between said two eccentric drives, which allows an advantageous adjustment of the needle movement to the advancement of the non-woven material when the support is guided parallel with respect to itself. For this purpose the connecting rod of the additional eccentric drive forms a parallelogram of links with the connecting rod of the synchronously revolving eccentric drive of the two other eccentric drives, which ensures the parallel guidance of the support and thus a swivel-free needle penetration into the non-woven material. Since already a comparatively small mutual offset of the angular position of the two eccentric drives revolving in opposite directions will produce a curved path for the support with a respective component in the direction of passage of the non-woven material, the horizontal component of the needleboard drive can be adjusted in a sensitive way to the respective conditions via the phase shift of the oppositely driven eccentric drives, namely with a relatively low amount of constructional effort when the mutually oppositely driven eccentric drives are driven via separate motors which with respect to their mutual rotional angle position are adjustable through a control device. As a result, only a control intervention is thus necessary in order to change the rotational angle position of one of the motors with respect to the other motor in order to enable the setting of the needboard advance in the direction of passage of the non-woven material, which naturally can also be performed during the needling process.
Although an additional eccentric drive is sufficient for the parallel guidance of the support, particularly simple constructional conditions are obtained with respect to the balancing of masses when two additional eccentric drives are provided which revolve synchronously with one each of the two other eccentric drives and form a parallelogram of links each with the same. In this case, the eccentric drives forming a parallelogram of links each for guiding the support can be drivably connected and be driven via a motor each. Another possibility is assigning each eccentric drive with a separate motor which is controllable with respect to speed and rotational angle position, which means drive motors with coinciding speed and rotational angle position for the eccentric drives forming a parallelogram of links.